1. Technical Field of the Invention
The present invention relates to a method of repairing an integrated electronic circuit.
2. Description of Related Art
The production of an electronic circuit with a high level of integration requires the use of expensive lithography masks. These masks define in particular the electrical connections between defined conducting parts of the circuit. Frequently an error in the design or the production of the lithography masks has the effect of omitting or of adding an electrical connection compared with the artwork of the circuit that has to be fabricated.
When the use of an erroneous lithography mask has the effect of omitting an electrical connection, those skilled in the art know how to repair the electronic circuit by restoring the missing electrical connection. To do this, an additional step is carried out during the production of the metallization level that corresponds to the missing electrical connection. This step is carried out after exposure of the masking resist deposited on the circuit using the erroneous lithography mask and before deposition of the metal. When the resist is a positive resist, the step consists of an additional exposure of the resist at the point of the missing connection. It is exposed either to an electron beam or to ultraviolet radiation through an additional mask produced for this purpose. The resist is then sensitized at the point of the missing connection and can be dissolved at this point at the same time as the resist parts that were sensitized during the initial exposure. The metal then deposited on those parts of the circuit that correspond to the dissolved resist parts form electrical connections, that include the electrical connection omitted during the design of the erroneous lithography mask.
There is a need for a way to repair an integrated circuit when a lithography mask used for producing the circuit includes an error of the type that causes the formation of an undesirable electrical connection.